Divx is format.
VLC is media player.
VLC can play standalone mediafiles or streams encoded with divx. It's not just divx, VLC can reproduce any media format except a few special ones (can't decode Bink&Smacker, EAlayer and such not widely used stuff).
Unlike every other media player out there, VLC doesn't use system codecs and can't fall into a codec hell.
Generally, VLC is the best overall player that exists.
However, old winamp (2.51 IIRC) has better designed audio playlists and when it comes to subtitles, BSplayer has better options than VLC (possibility to display them under the picture doesn't exist in VLC, also VLC cannot override font/color formatting in ASS subtitles). Keep in mind that both winamp and BSplayer can't work without appropriate codecs for each media format you're trying to reproduce through them.
Also, while VLC can reproduce variety of static/animated picture formats, IrfanView is unbeatable in that area as is easier to use.